style: Document & refactor rooms/event_handler service

src/service/rooms/event_handler/fetch_state.rs

@@ -1,6 +1,6 @@
 use std::collections::{HashMap, hash_map};
 
-use conduwuit::{Err, Event, Result, debug, debug_warn, err, implement};
+use conduwuit::{Err, Event, Result, debug, debug_warn, err};
 use futures::FutureExt;
 use ruma::{
 	EventId, OwnedEventId, RoomId, ServerName, api::federation::event::get_room_state_ids,
@@ -9,78 +9,81 @@ use ruma::{
 
 use crate::rooms::short::ShortStateKey;
 
-/// Call /state_ids to find out what the state at this pdu is. We trust the
-/// server's response to some extend (sic), but we still do a lot of checks
-/// on the events
-#[implement(super::Service)]
-#[tracing::instrument(
-	level = "debug",
-	skip_all,
-	fields(%origin),
-)]
-pub(super) async fn fetch_state<Pdu>(
-	&self,
-	origin: &ServerName,
-	create_event: &Pdu,
-	room_id: &RoomId,
-	event_id: &EventId,
-) -> Result<Option<HashMap<u64, OwnedEventId>>>
-where
-	Pdu: Event + Send + Sync,
-{
-	let res = self
-		.services
-		.sending
-		.send_federation_request(
-			origin,
-			get_room_state_ids::v1::Request::new(event_id.to_owned(), room_id.to_owned()),
-		)
-		.await
-		.inspect_err(|e| debug_warn!("Fetching state for event failed: {e}"))?;
-
-	debug!("Fetching state events");
-	let state_ids = res.pdu_ids.iter().map(AsRef::as_ref);
-	let state_vec = self
-		.fetch_and_handle_outliers(origin, state_ids, create_event, room_id)
-		.boxed()
-		.await;
-
-	let mut state: HashMap<ShortStateKey, OwnedEventId> = HashMap::with_capacity(state_vec.len());
-	for (pdu, _) in state_vec {
-		let state_key = pdu
-			.state_key()
-			.ok_or_else(|| err!(Database("Found non-state pdu in state events.")))?;
-
-		let shortstatekey = self
+impl super::Service {
+	/// Call /state_ids to find out what the state at this pdu is. We trust the
+	/// server's response to some extent (sic), but we still do a lot of checks
+	/// on the events
+	#[tracing::instrument(
+		level = "debug",
+		skip_all,
+		fields(%origin),
+	)]
+	pub(super) async fn fetch_state<Pdu>(
+		&self,
+		origin: &ServerName,
+		create_event: &Pdu,
+		room_id: &RoomId,
+		event_id: &EventId,
+	) -> Result<Option<HashMap<u64, OwnedEventId>>>
+	where
+		Pdu: Event + Send + Sync,
+	{
+		let res = self
 			.services
-			.short
-			.get_or_create_shortstatekey(&pdu.kind().to_string().into(), state_key)
+			.sending
+			.send_federation_request(
+				origin,
+				get_room_state_ids::v1::Request::new(event_id.to_owned(), room_id.to_owned()),
+			)
+			.await
+			.inspect_err(|e| debug_warn!("Fetching state for event failed: {e}"))?;
+
+		debug!("Fetching state events");
+		let state_ids = res.pdu_ids.iter().map(AsRef::as_ref);
+		let state_vec = self
+			.fetch_and_handle_outliers(origin, state_ids, create_event, room_id)
+			.boxed()
 			.await;
 
-		match state.entry(shortstatekey) {
-			| hash_map::Entry::Vacant(v) => {
-				v.insert(pdu.event_id().to_owned());
-			},
-			| hash_map::Entry::Occupied(_) => {
-				return Err!(Database(
-					"State event's type and state_key combination exists multiple times: {}, {}",
-					pdu.kind(),
-					state_key
-				));
-			},
+		let mut state: HashMap<ShortStateKey, OwnedEventId> =
+			HashMap::with_capacity(state_vec.len());
+		for (pdu, _) in state_vec {
+			let state_key = pdu
+				.state_key()
+				.ok_or_else(|| err!(Database("Found non-state pdu in state events.")))?;
+
+			let shortstatekey = self
+				.services
+				.short
+				.get_or_create_shortstatekey(&pdu.kind().to_string().into(), state_key)
+				.await;
+
+			match state.entry(shortstatekey) {
+				| hash_map::Entry::Vacant(v) => {
+					v.insert(pdu.event_id().to_owned());
+				},
+				| hash_map::Entry::Occupied(_) => {
+					return Err!(Database(
+						"State event's type and state_key combination exists multiple times: \
+						 {}, {}",
+						pdu.kind(),
+						state_key
+					));
+				},
+			}
 		}
+
+		// The original create event must still be in the state
+		let create_shortstatekey = self
+			.services
+			.short
+			.get_shortstatekey(&StateEventType::RoomCreate, "")
+			.await?;
+
+		if state.get(&create_shortstatekey).map(AsRef::as_ref) != Some(create_event.event_id()) {
+			return Err!(Database("Incoming event refers to wrong create event."));
+		}
+
+		Ok(Some(state))
 	}
-
-	// The original create event must still be in the state
-	let create_shortstatekey = self
-		.services
-		.short
-		.get_shortstatekey(&StateEventType::RoomCreate, "")
-		.await?;
-
-	if state.get(&create_shortstatekey).map(AsRef::as_ref) != Some(create_event.event_id()) {
-		return Err!(Database("Incoming event refers to wrong create event."));
-	}
-
-	Ok(Some(state))
 }